MALAT1 and Parkinson disease: Consistently, transfection of si-MALAT1 dramatically abated down-regulation of miR-124 induced by MPP+ in SH-SY5Y cells (Fig. 5b), suggesting that MALAT1 could negatively regulate miR-124 expression in MPTP-induced PD mouse model and MPP+-intoxicated SH-SY5Y cells.